title: The effect of over-commitment and reward on trapezius muscle activity and shoulder, head, neck, and torso postures during computer use in the field.
abstract: BACKGROUND
  Because of reported associations of psychosocial factors and computer related musculoskeletal symptoms, we investigated the effects of a workplace psychosocial factor, reward, in the presence of over-commitment, on trapezius muscle activity and shoulder, head, neck, and torso postures during computer use.
  
  
  METHODS
  We measured 120 office workers across four groups (lowest/highest reward/over-commitment), performing their own computer work at their own workstations over a 2-hr period.
  
  
  RESULTS
  Median trapezius muscle activity (P = 0.04) and median neck flexion (P = 0.03) were largest for participants reporting simultaneously low reward and high over-commitment. No differences were observed for other muscle activities or postures.
  
  
  CONCLUSIONS
  These data suggest that the interaction of reward and over-commitment can affect upper extremity muscle activity and postures during computer use in the real work environment. This finding aligns with the hypothesized biomechanical pathway connecting workplace psychosocial factors and musculoskeletal symptoms of the neck and shoulder.
authors.affiliation: Department of Environmental Health, Harvard University, Boston, MA, USA.
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Bruno Garza
authors.forename: Belinda H W
authors.initials: BH
authors.lastname: Eijckelhof
authors.forename: Maaike A
authors.initials: MA
authors.lastname: Huysmans
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Catalano
authors.forename: Jeffrey N
authors.initials: JN
authors.lastname: Katz
authors.forename: Peter W
authors.initials: PW
authors.lastname: Johnson
authors.forename: Jaap H
authors.initials: JH
authors.lastname: van Dieen
authors.forename: Allard J
authors.initials: AJ
authors.lastname: van der Beek
authors.forename: Jack T
authors.initials: JT
authors.lastname: Dennerlein
mesh_terms: D000328:Adult; D001696:Biomechanical Phenomena; D003201:Computers; D004576:Electromyography; D005260:Female; D006257:Head; D006801:Humans; D008297:Male; D008875:Middle Aged; D009333:Neck; D019547:Neck Pain / Q000503:physiopathology* / Q000523:psychology; D009784:Occupational Diseases / Q000503:physiopathology* / Q000523:psychology; D011187:Posture / Q000502:physiology*; D012201:Reward; D020069:Shoulder Pain / Q000503:physiopathology* / Q000523:psychology; D064171:Superficial Back Muscles / Q000503:physiopathology*; D060726:Torso; D016526:Workload / Q000523:psychology; D017132:Workplace / Q000523:psychology; D055815:Young Adult
keywords: MSDs; VDT; exposure assessment; office ergonomics; psychosocial